Since hair is daily exposed to physical stimulation by daily hair care routines such as heat drying with a hair dryer and brushing, and chemical stimulation by shampooing, permanent weaving, dyeing and bleaching, it is in a damaged state with a partial loss of components or structure. A change in hair quality due to ageing accelerates this damage and also causes the loss of suppleness which healthy hair inherently possesses.
It is a common practice to protect or repair hair in a damaged state by making up for the lost components or structure or an analogue thereof. Interaction (affinity) between a protecting base and hair is considered to be important for developing a protecting or restoring function, and thus a method of using a sphingolipid or protein derivative as a protecting base has been employed widely as a useful technique. For example, proposed is a hair cleansing composition containing a surfactant composed of an anionic surfactant and a bipolar ionic surfactant, a cationic polymer, and ceramide or glycoceramide (Japanese Patent Application Laid-Open No. 59443/1996). The composition however cannot contain a sufficient amount of a protecting base such as a ceramide or glycoceramide because it has a high melting point and is liable to crystallize. Moreover, even a slight amount of the protecting base incorporated in the composition does not readily penetrate into hair. No method has yet been proposed to feed hair with a sufficient amount of a protecting base. The conventional hair cleansing compositions are therefore accompanied by the problem that the protecting base incorporated therein cannot fully function.